There has been voluminous research conducted on the biochemistry of injury and disease conditions. Conversely, there has been little or no research directed at possible adverse reactions to inhaled atmospheric gases. Specifically, outside of its known potential for adverse reactions in deep sea diving, no knowledge has been developed about any undesirable reactions to inhaled nitrogen. Based on the research of the inventor, VanDeripe, Toxicology Methods 11:107-126 (2001), it becomes clear that gases other than oxygen can enter and fill mitochondria, and since these gases are not usable for oxidative metabolism, they might be expected to interfere with the production of ATP and therein compromise mitochondrial membrane integrity. Whereas this phenomenon might be expected with volatile anesthetics, what is discovered in this invention is the very real potential danger from constantly inhaled atmospheric nitrogen gas in selected injury and disease conditions. To counter these adverse effects, the instant invention proposes the use of total body nitrogen washout methodology which involves the inhalation of nitrogen-free gas mixtures composed of oxygen and helium: see VanDeripe, Medical Hypotheses 62: 294-6 (2004). Disclosures of the use of helium and oxygen on the treatment of strokes and heart attacks include U.S. Pat. No. 6,001,332 (Garrett), U.S. Pat. No. 6,899,103 (Hood et al) and U.S. Pat. No. 6,983,749 (Kumar et al.), but they clearly involve different parameters and mechanisms of action. Garrett anecdotally notes anti-arrhythmic activity for helium-oxygen mixtures in acute myocardial infarction, but without further discussion or explanation. Conversely, Wade, et al. report an absence of anti-arrhythmic activity in patients with spontaneous premature ventricular beats; see Undersea Biomed. Res. 6:313-8 (1979). Piffare, et al. The Journal of Thoracic and Cardiovascular Surg. 60:648-52 (1970) noted short term ant-arrhythmic activity for inhaled oxygen-helium mixtures in an animal model of permanent coronary artery dissection, but highly effective mixtures also contained air (nitrogen). Like Pifarre, Hood and Kumar also allow the admixture of air and or nitrogen to the inhaled gases, contrary to the nitrogen-free gas mixtures of this invention. Kumar, et al. use helium oxygen gas mixtures in hypothermia technology to decrease the metabolism of the entire body. Conversely, the object of this invention is to increase the metabolism in ischemic mitochondria of the myocardium. An experimental study employing the technology of this invention has been reported in a rat stroke model: see Pan, et al. Exp. Neurol. 205: 587-90 (2007).